Dianhydrogalactitol (1,2:5,6 dianhydrogalactitol or DAG) is one of a number of hexitols or hexitol derivatives having significant pharmacological activity, including chemotherapeutic activity. In particular, dianhydrogalactitol has been suggested for use in chemotherapy, such as in U.S. Pat. No. 7,157,079 to Nielsen et al., incorporated herein by this reference.
Dianhydrogalactitol has activity against a number of neoplasms. However, if dianhydrogalactitol is to be used successfully as a therapeutic agent, an extremely high degree of purity and the removal of impurities is essential. The presence of impurities can lead to undesirable side effects. One example occurred a number of years ago, when impurities present in a batch of the amino acid tryptophan, a normal constituent of protein, were responsible for a significant outbreak of eosinophilia-myalgia syndrome, which caused a large number of cases of permanent disability and at least 37 deaths. This is particularly important if the therapeutic agent such as dianhydrogalactitol is to be employed in patients with compromised immune systems or liver or kidney dysfunction, or in elderly patients. Such patients may experience a greater incidence of undesirable side effects owing to their sensitivity to contaminants.
One of the impurities found in preparations of dianhydrogalactitol is dulcitol. Other impurities exist in preparations of dianhydrogalactitol as well, depending on their method of preparation.
Therefore, there is a need for improved analytical methods to detect impurities and degradation products in preparations of dianhydrogalactitol to provide preparations of greater purity that are less likely to induce side effects when dianhydrogalactitol is administered for therapeutic purposes.